Method of determining motorcycle power output

ABSTRACT

A motorcycle power take-off drive system is disclosed for driving a dynamometer from either a chain drive or a shaft drive motorcycle having either right or lefthand chain or shaft drive connections. A support housing is straddled by the rear frame elements of the motorcycle with a support shaft extending into the axle openings in the frame to support the frame. A drive shaft sleeve coaxially surrounds the support shaft and has either a sprocket for connection to the chain of a chain driven motorcycle attached to one end or an internally splined sleeve drivingly connectable to an externally splined output drive member of a shaft drive motorcycle. A low-friction chain connects the drive shaft sleeve to a power drive shaft drivingly connected to a dynamometer.

This is a division of my copening Application Ser. No. 953,192 filed onOct. 17, 1978, U.S. Pat. No. 4,196,617.

This invention is in the field of power test equipment and is morespecifically directed to a unique power take-off apparatus for directlytransmitting the power from a motorcycle engine to a driven device andwhich is of particular use in driving a dynamometer.

A problem common to practically all prior known motorcycle power takeoffdevices is lack of versatility in that such devices have to be speciallyset up and frequently makeshift rigged in order to be used withdifferent motorcycle designs.

Previously known devices have been employed for measuring the horsepoweroutput of motorcycle engines; however, these devices have not providedsatisfactory operation for a variety of reasons. More specifically, theprior known devices in many instances have failed to provide an accurateindication of the engine horsepower and have also been difficult andeven dangerous to use. An additional problem is that many of the priorknown devices requires several operators and cannot be used by a loneoperator.

The primary deficiency of the conventional prior known dynamometer drivesystem for motorcycles of the type employing a pair of horizontalrollers on which the rear wheel of the motorcycle is positioned so thatoperation of the motorcycle effects rotation of the rollers is that suchsystems can only operate at low speed. Also, operation of the motorcycleresults in a substantial forward force being applied to the motorcycleby the reaction between the tire and the supporting rollers and it isconsequently necessary that the motorcycle be strongly and securelyattached to restraining and support means. Any failure of therestraining and support means of the motorcycle would permit themotorcycle to spring clear of the dynamometer drive assembly to thegreat danger of those in the work area. Thusly, it is absolutelyessential that the motorcycle be securely attached in position prior tothe initiation of a test run and the wide variations in size, shape andconstruction of motorcycles creates substantial difficulty in providingtest equipment capable of use with a wide variety of motorcycle types.Another shortcoming of drive systems of the foregoing type is that theycannot be used with knobby tires.

Additionally, the driving of a dynamometer in the foregoing manner byuse of the rear wheel tire engagement with the supporting rollers doesnot always provide a good indication of engine horsepower due to varyingfrictional characteristics in the rear wheel bearing assembly, theparticular type of tire employed on the wheel, and vibrations resultantfrom rotation of the wheel.

Thusly, the presently known motorcycle dynamometer drive systems havenot provided satisfactory results in that they are difficult to use whentesting a wide variety of motorcycle types, are sometimes quitedangerous to use and fail to provide accurate reliable results.

Other systems have employed long, cumbersome and dangerous chain drivesfor driving the dynamometer. Such systems can only be used with chaindrive motorcycles and are consequently of limited value in view of theincreasing number of shaft driven motorcycles.

Therefore, it is the primary object of this invention to provide a newand improved dynamometer drive system for use with motorcycles.

A further object of the invention is the provision of a new and improvedmotorcycle dynamometer drive system which is usable with a wide varietyof motorcycle sizes and types.

Yet another object of the present invention is the provision of a newand improved motorcycle dynamometer test system which eliminates usageof the motorcycle rear wheel as part of the drive train for thedynamometer.

A further object is the provision of a power take-off for use witheither a chain or shaft driven motorcycle.

Achievement of the foregoing objects is enabled by the preferredembodiment of the invention through the provision of a floor-mountedhousing having a horizontal driven shaft sleeve mounted on bearings inthe housing and extending transversely of the housing on opposite sidesof the housing in a cantilever manner. A support shaft axiallypositioned in the housing with respect to the driven shaft sleeveextends into the openings in the rear frame portions of a motorcycleframe in which the motorcycle rear axle is normally positioned; suchrear frame portions straddle the housing. The driven shaft sleeve iscoaxial with the support shaft and can have a driven sprocket attachedto one of its ends externally of the housing for receiving a drive chainextending from the output of the motorcycle transmission when themotorcycle is of the type having a chain drive. Alternatively, thedriven shaft sleeve can be fitted with an internally splined driveconnector dimensioned to matingly couple with the externally splineddrive sleeve of a shaft drive type motorcycle normally received in thewheel of the motorcycle for driving same. In both cases, both thesprocket and the internally splined drive sleeve are removablyconnectable to the driven shaft sleeve by attachment bolts and arepositioned with respect to the motorcycle in exactly the same positionas the same items on the motorcycle rear wheel.

A power output shaft is also mounted in the housing and is connected tothe driven shaft sleeve by a low-friction chain and is externallyconnected on the housing to a conventional dynamometer for driving thedynamometer upon operation of the motorcycle engine. Thusly, the subjectinvention permits the connection of either a shaft drive or a chaindrive motorcycle to the dynamometer. Moreover, since the rear wheel ofthe motorcycle is removed, restraining and support means are notrequired for the motorcycle in that the connection of its rear frame forcomponents to the support shaft provides a certain and sure support forthe motorcycle without any danger of it breaking loose and becoming ahazard to those in the vicinity. The support shaft in effect takes theplace of the rear axle of the motorcycle and constitutes the solesupport for the rear end of the motorcycle; consequently, the system canbe used with practically any type of motorcycle and special frames, jigsor the like for supporting the motorcycle is not required even forunusual motorcycle designs.

A better understanding of the manner in which the preferred embodimentachieves the foregoing objects of the invention will be enabled when thefollowing written description is considered in conjunction with theappended drawings, in which:

FIG. 1 is a side elevation view of a chain-drive motorcycle drivinglyconnected to the drive system comprising the preferred embodiment;

FIG. 2 is a perspective view of the embodiment of FIG. 1;

FIG. 3 is a sectional view taken along lines 3--3 of FIG. 2;

FIG. 4 is a sectional view taken along lines 4--4 of FIG. 3;

FIG. 5 is a side elevation view illustrating the operation of thepreferred embodiment with a shaft-drive motorcycle;

FIG. 6 is a sectional view taken along lines 6--6 of FIG. 5; and

FIG. 7 is an exploded perspective view of drive components of theembodiment of FIGS. 5 and 6.

Attention is initially invited to FIG. 1 of the drawings whichillustrates a motorcycle of conventional chain-drive design having atransmission case 12 from which an output shaft (not shown) is provided.A sprocket on the output shaft is connected to the motorcycle drivechain 14 with the rear portion of the motorcycle being supported by thehousing of the preferred embodiment of the invention which is generally16. It will be observed that the rear wheel of the motorcycle is removedand that the rear frame elements 18 and 20 of the motorcycle straddlethe housing and include openings 22 which normally receive the axle ofthe rear wheel of the motorcycle. However, a motorcycle frame supportshaft means 26 mounted in main side plates 28 and 30 of the housingextends through the openings 22 in the frame and is held in position bya bolt head 32 on one end of the shaft and a tightening nut 33 on anopposite end in an obvious manner. Additionally, the support shaft alsosupports spacer sleeves 34 extending between bearing means 36 and therespective motorcycle frame elements 18 and 20 with the number and sizeof such sleeves depending upon the distance between the rear frameelements 18 and 20.

The bearings 36 provide a rotary connection between the support shaft 26and a driven shaft sleeve member 40 which is supported for rotation bybearings 42 mounted in the side plates 28 and 30. Consequently, thedriven shaft sleeve 40 is capable of rotation both with respect to thehousing and the support shaft 26. A radial flange 44 is drivinglyconnected to the driven shaft sleeve 40 to form a unitary constructiontherewith and a sprocket is connected to the radial flange 44 by boltmembers 46 as best shown in FIG. 4. The motorcycle drive chain 14 isfitted over the sprocket 45 so that driven movement of the chain 14serves to rotate the sprocket 45, flange 44 and driven shaft sleeve 40in an obvious manner.

A power drive shaft 50 mounted in bearings 52 in the casing side plates28 and 30 is drivingly connected by a low-friction chain 54 mounted on asprocket 58 drivingly connected to the drive shaft sleeve 40 internallyof the housing and a sprocket 60 keyed to the power drive shaft 50. Thelow-friction chain 54 is a Morse HI-VO chain of extremely high powertransmission efficiency. Lubrication of the low-friction chain 54 isprovided by a sump 72 which is maintained at a proper level through afill tube 74 as shown in FIG. 3.

Power drive shaft 50 is connected by a coupling 62 to a conventionaldynamometer 64 as shown in FIG. 2. While the preferred embodimentillustrates the system in use for driving the dynamometer 64, it shouldbe understood that the inventive drive system can also be used fordriving other apparatus such as generators, pumps or the like ifdesired. A stable support for the rear portion of the motorcycle isprovided by virtue of the fact that the housing includes a lower baseplate 70 of sufficient dimensions to provide substantial lateralstability. Another point of significance is the fact that the radialflange 44 and associated sprocket 45 can be mounted on either side ofthe housing for accommodating motorcycles having the drive chain oneither the right or left side of the motorcycle frame.

Turning now to FIGS. 5 through 7, it is noted that these figures aredirected to the use of the subject invention for receiving power from ashaft-drive motorcycle. It will be observed that the only differencefrom the device of the first embodiment is that an internally splinedsleeve 80, which is best illustrated in FIG. 7, is connected by boltmeans 46 to the radial flange 44 in place of the sprocket means 45 ofthe first embodiment. FIG. 6 illustrates the manner of connection withthe frame of the shaft-driven motorcycle in which the lefthand frameelement 20 is engaged with the head 32 of shaft 26 which providessupport for the frame. The other end of the shaft 26 extends through thehousing 84 of the rear wheel driving mechanism of the motorcycle whichincludes a drive shaft 86 from the output of the motorcycle transmissiondrivingly connected to a pinion 88 meshing with a ring gear 90 which iskeyed on a ring gear spacer 92 mounted for rotation in the housing andhaving an externally splined end portion male sleeve 94. The splines onthe externally splined male sleeve 94 mesh with the internal splines ofthe internally splined female sleeve 80 so that when the parts arepositioned as shown in FIG. 6, the internally splined sleeve 80 isdriven via the elements 86, 88, 90, 92 and 94 in an obvious manner. Itshould be observed that the support shaft 26 extends through the area ofthe housing 84 normally occupied by the rear axle of the motorcycle.

Thusly, both embodiments of the invention permit a motorcycle to beconnected to the system without any need for removing saddlebags,exhaust pipes or the like with the system being connectable topractically any type of motorcycle both right and lefthand drive whichcan either be of the chain or shaft type.

Numerous modifications of the subject invention will undoubtedly occurthose of skill in the art and it should be understood that the spiritand scope of the invention is to be limited solely by the appendedclaims.

I claim:
 1. A method of determining the power output of a motorcycleengine of a chain-drive motorcyle comprising the steps of:removing therear wheel from the motorcycle to be tested; connecting the axlereceiving openings of the motorcycle frame to a fixedly positionedsupport shaft; connecting the motorcycle chain to input drive meansdrivingly connected to a dynamometer; and operating the motorcycleengine to determine the power output thereof.
 2. A method of determiningthe power output of a motorcycle engine of a shaft-drive motorcyclehaving an externally splined drive sleeve normally drivingly connectedto the rear wheel of the motorcycle, said method comprising the stepsof:removing the rear wheel from the motorcycle; connecting the axlereceiving openings of the motorcycle frame to a fixedly positionedsupport shaft; matingly connecting the externally splined drive sleeveto an internally splined drive sleeve drivingly connected to adynamometer; and operating the motorcycle engine to determine the poweroutput thereof.